There are presently known water heaters or boilers for mounting on a floor and having valves arranged at the top or at the bottom. Similarly, there exist water heaters for mounting on a wall and connected at the bottom.
The present design is based on permanently tight tubing to the valves and the tank of the water heater. However, in practice, one or several components will sooner or later start leaking, in the range from some drops per hour and to a complete blowout.
If it was decreed by law that all water heaters should be arranged in rooms with a floor drain water leakage would not have occurred, at least not in the present extent, but such a law does not exist and the installer can thus make his completely own decisions and take the risks that no water damages will later occur.
A recently implemented requirement from water heater manufacturers states that if the water heater is not arranged in a room provided with a floor drain, a water stop valve (with a function similar to what is used in some dishwashing machines) has to be mounted. This water stop valve thus functions by means of a sensor line which contacts the floor, and if water on the floor should be sensed, the valve will close the cold water inlet to the water heater. The water heater will thus not be replenished with cold water when a water leakage is occurring, but the water volume already contained in the water heater will not be influenced by the water stop valve. For a water heater with a capacity of 200 liters, as much as 200 liters will then be able leak out and cause large and expensive water damages in the building. In countries in which the agglomeration of buildings is dominated by wooden structures, such as in Norway and in the remaining Nordic countries, the costs will inherently be particularly large due to such leakages, and at the same time the risk of such damages is larger in a relative perspective due to the risk of frost.
In this context it should be mentioned that the total costs in Norway per year related to water damages amount to in the order of 3 billon Norwegian kroner.
As to prior art, US 20080017135 A1 and US 20060169321 A1 disclose two respective leakage protection bags to be drawn around a water heater and having an outlet at the bottom, and U.S. Pat. No. 5,881,762 A discloses a bottom tray with an outlet to be retrofitted below a water containing device, such as a water heater.